Demonstrating efficacy of technology on human subjects is an essential part of successful achievement of commercialization of such technology. Human trials aimed at identifying benefits of a technology, such as a skin benefit technology, often require three to six months duration to visualize measurable effect. For example, retinoids are a particularly potent anti-aging technology in skin care, however, even retinoids require this lengthy period to elicit a visual change. Shorter term, e.g. 1 week, human studies may be developed. These shorter term stuedes are especially useful for screening or ranking a number of potential actives. Short term human studies rely on the collection of skin tissue samples which are typically undertaken by physicians taking relatively invasive biopsies of the skin, either full thickness (dermis and epidermis) or shave biopsies. These invasive skin sampling methods generally provide more tissue than is actually required for many assays for biomarkers that may indicate long term clinical efficacy after short term treatment.
Currently used sampling techniques include the following: full thickness punch biopsies, “nick” (small shave) biopsies and blister biopsies. Full thickness punch biopsies entail use of a razor-edged circular punch and a scalpel to remove a piece of tissue that can extend further than the dermis. “Nick”, or small shave, biopsies involve the use of a scalpel to remove a pinched up portion of the skin surface. The full thickness punch biopsy and the shave biopsy techniques present the subject with considerable discomfort, require anesthesia (requiring administration by a physician), and pose potential harm. Methods of this type, involving gross removal of skin tissue in a procedure that is essentially surgical include: U.S. Pat. No. 5,325,857, U.S. Pat. No. 5,394,886, U.S. Pat. No. 5,380,337 and U.S. Pat. No. 5,570,700. Blister biopsies require the use of a vacuum applied to the skin surface to produce a blister, which is removed by scalpel. Suction blister epidermal sampling provides the desired epidermal samples, however, this method requires a blistering period of about two hours, during which time changes can occur to the biochemistry of the epidermal skin cells, such as the degradation of RNA.
Dermabrasion tools and techniques used in treating pitted and disfigured skin involve what are essentially power tools and involve no harvesting and processing of sampled tissue material. U.S. Pat. No. 6,423,078 relates to surgical abrasion using diamond grit and U.S. Pat. No. 5,800,446 relates to an abrasive tip, however, both of these devices remove considerably more tissue than they are able to harvest.
There is a need for a sampling device and technique that does not require the presence of a physician, is minimally invasive, does not remove excess tissue, can be done with minimal discomfort and that provides a sample large enough for modern biochemical analysis.